Asclepias linaria
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Asclepias linaria |
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Asclepias linaria is a species of silk plants ( Asclepias ) in the subfamily of the silk plants (Asclepiadoideae) within the family of dog poison plants (Apocynaceae). It isnative tothe southwest USA to northern Mexico .
description
Appearance and leaf
Asclepias linaria grows as a perennial herbaceous plant with a woody base, or as a low, fragile shrub . It reaches heights of 50 to 200 cm (or 30 to 150 cm). The relatively slender, multi-branched stem axes stand upright or are ascending and can be more or less woody. They bear the scars of the shed leaves. The young shoot axes are initially finely haired and later bald.
The densely alternate and almost spirally arranged leaves are sessile. The sparsely hairy or bald leaf blades are needle-shaped with a length of 2 to 5 cm and a width of about 1 mm. The leaf margins and the tip of the blade are bent towards the underside.
Inflorescence and flower
The flowering period extends from April to November. Almost terminal or lateral and solitary at some of the upper nodes ( nodes ) on a moderately slender, 0.5 to 2 cm long, hairy inflorescence stem, standing, dilded inflorescence contains few to many flowers. The flower stalks are slender, 1.5 to 2 cm long and also hairy.
The relatively small, hermaphrodite flowers are radial symmetry and five-fold. The five finely hairy sepals are lanceolate with a length of about 3 mm and only fused at their base. The corolla is wheel-shaped and bent back. The greenish white, usually slightly rosé or purple reddened petals have 4 to 5 mm long petal tips. The short conical and about 1 mm high and equally broad-stalked gynostegium is orange or cream-colored. With a length of 3 to 4 mm broadly ovate, erect or ascending, staminal secondary corolla lobes are hood-shaped. The inner secondary process is horn-shaped, lies almost completely on the staminal corolla lobe, but is shorter than this. The stylus head is cut off conically, about 1.5 mm long and 2.5 to 3 mm wide. The wings of the anthers are 1 to 1.2 mm and the corpusculum 0.25 mm long. The pollinia measure 0.8 mm in length.
Fruit and seeds
Upright fruits stand on curved fruit stalks. The smooth, slightly hairy to bald follicles are spindle-shaped with a length of 4 to 5 cm and a width of 1 to 2 cm wide. The seeds, which are oval in length, are about 6 mm long and have white hairs up to about 2 cm long.
similarities
Asclepias linaria is quite uniform over the entire area and belongs to the species of the genus Asclepias that are most lignified. The young plants can easily be mistaken for pine seedlings due to the needle-shaped leaves.
Synecology
Asclepias linaria is an important food plant of the monarch butterfly ( Danaus plexippus ) in its range .
Occurrence
The distribution area of Asclepias linaria extends from northern Mexico to the southwestern USA (states California , Arizona and New Mexico ). Find locations in Mexico are available for the states of Chihuahua , Coahuila , Durango , Guanajuato , Jalisco , México , Michoacán , Morelos , Nuevo León , Oaxaca , Puebla , Querétaro , San Luis Potosí , Sonora , Tamaulipas , Tlaxcala , Veracruz , the central Zacesatecas district and the capital Mexico city .
The vertical distribution extends between altitudes of about 800 to 1750 meters. Asclepias linaria occurs in open oak , pine or juniper forest areas on dry limestone ridges, stony hills, sandy slopes on volcanoes, canyons and dry valleys. It also spreads from these locations to dry pastureland and wasteland.
Taxonomy
The first publication of Asclepias linaria was carried out in 1791 by Antonio José Cavanilles in Icones et Descriptiones Plantarum , 1, page 42, Table 57. synonyms for Asclepias linaria Cav. are: Asclepias filiformis Sessé & Moc. Greene , Asclepias pinifolia . The specific epithet linaria means flat-like .
swell
literature
- Robert E. Woodson, Jr .: The North American Species of Asclepias L. , In: Annals of the Missouri Botanical Garden , Volume 41 (1), pp. 1-211, St. Louis, Mo., 1954 Scanned at biodiversitylibrary. org . (Description of Asclepias linaria on pp. 113–114)
- Eric Sundell: Asclepiadaceae Milkweed Family. In: Journal of the Arizona-Nevada Academy of Science , Volume 27, Issue 2, 1993, pp. 169-187. PDF
Individual evidence
- ↑ Woodson (1954: p. 113/4)
- ↑ a b Sundell (1994: p. 178)
- ^ Southwest Monarch Study
- ↑ United States Department of Agriculture Plants Profile: Asclepias linaria Cav.
- ^ Asclepias linaria at Tropicos.org. Missouri Botanical Garden, St. Louis
